docs: def authenticate_keystone_user(self, keystone, user, password, tenant):
          """Authenticates a regular user with the keystone public endpoint."""
          self.log.debug('Authenticating keystone user ({})...'.format(user))
          ep = keystone.service_catalog.url_for(service_type='identity',
                                                interface='publicURL')
          keystone_ip = urlparse.urlparse(ep).hostname
  
          return self.authenticate_keystone(keystone_ip, user, password,
                                            project_name=tenant)